1. Field of the Invention
The present invention relates generally to backpacks, and more particularly, to ergonomic backpacks having a compression system that compresses the contents of the backpack. The system, operating like a regular backpack, allows the user to carry heavier loads for a longer period of time with less fatigue and discomfort.
2. Description of Related Art
The use of backpacks for carrying loads for different purposes is well known. In recent years, the popularity of the backpack for daily use has increased significantly. Students, for example, use backpacks to carry their school related materials. Hikers use backpacks to carry hiking gear, food and drinks. Young professionals use backpacks to carry their documents, computers, etc.
While regular backpacks are suitable for carrying loads, they are not suitable for carrying heavy loads. Even so, students have to use backpacks to carry heavy loads relative to their body weights to school every day in order to bring the necessary school supplies and books.
A serious disadvantage of the backpacks normally used by students when carrying heavy loads is discomfort to the user's lower back, which could potentially lead to body damage. In theory, the best placement of the load of a backpack is immediately above the human body center of the pelvis, as illustrated in FIG. 2B, which shows an ergonomic backpack with a load that is closer to the user's back and has a slightly higher center of gravity (“CG”). However, a conventional backpack sags with the load, which causes the load not only to move further away from the user's back but also to shift the center of the gravity below the human body center of the pelvis as shown in FIG. 2A. This creates stronger downward moment and makes the backpack feel much heavier to the user. Furthermore, the sagging of the backpack results in the user's back losing proper and comfortable support. As a result, the user cannot maintain proper back position and has to lean forward when carrying heavy loads for a while. Anyone who has seen students walking across a campus has witnessed the negative sagging effect of the backpack on students' postures. Once the spine alignment is improper and the muscles become stressed, the user feels discomfort, fatigue and pain, which could even result in injury to the back. This can be more harmful for younger students because frequent improper spine alignment caused by carrying heavy backpacks every day could potentially lead to poor posture problems.
Therefore, it is highly desirable to design an improved backpack, which is configured to be more comfortable when carrying a relatively heavy load. Whereas considerable efforts have been emphasized on new technologies in manufacturing backpacks, relatively less has been done to address the sagging effects of backpacks. U.S. Pat. No. 6,164,509 to Gausling et al. discloses a backpack with a compression system and an optional back support device. The system uses straps to reduce the sagging effect by pulling the backpack closer to the user's body. However, the complicated construction could increase manufacturing costs, which limits its implication in practice. Michael Collier et al. disclose a different compression system using straps in U.S. Pat. No. 7,204,399. Each shoulder strap has a first end connected at a junction of the top side and the body side, and a second end connected to the backpack body at a junction of the bottom side and the body side. Each of the straps extends through the bottom of the backpack, threaded through a D-ring attached to the lateral side and the outside, passes through the lateral side, and then threads through a second D-ring attached to the lateral side and the body side. When the straps are tied, the backpack is lifted and moved toward the back of the user. However, due to the extended strap being used in the process of lifting and compression, the user has to further pull down the straps in order to complete the process.
Reducing the sagging effect of a backpack may not automatically bring adequate back support to the user. Both the inventions discussed above and many others in the prior art do not provide a simple and effective way to jointly address the sagging and back support issues.
The instant invention results from a methodical attempt to resolve the above disadvantages of the backpack of the prior art.